That's not saying it might not be prudent or simply kinder to *withhold* your opinion, in some particular situation. But you should have a moral opinion to withhold and sometimes you will be called upon to express it.
Don't chicken out, even if they hate you or punish you for expressing an unpopular opinion.
You were not put on Earth to be popular. You were put here to follow in the steps of someone who was crucified for expressing unpopular opinions.